De Gea's form has come under scrutiny over the past two seasons and he has been culpable for each of the past two Premier League goals the Red Devils have conceded.
The Spain international saw a kick blocked into the net by Dominic Calvert-Lewin in the 1-1 draw with Everton in March and failed to stop a Steven Bergwijn shot last Friday as United were held to the same scoreline away to Tottenham, leading to heavy criticism from former captains Roy Keane and Gary Neville.
By contrast, Henderson has thrived during a loan spell with Sheffield United that is expected to be extended to cover the rest of the delayed 2019-20 season and could be stretched further to include 2020-2021.
Solskjaer has no doubt Henderson has the potential to claim a first-team spot at Old Trafford in future but has no reason to doubt De Gea for now.
"David is the best goalkeeper in the world," the United manager told reporters on Tuesday. "He has conceded two goals in games against City, Chelsea, Tottenham, Everton. We've gone on a run not conceding goals.
"Of course, the Everton one is a freak one. This one [against Spurs], he cannot save it. He makes great saves, he wins games for us, I still think he's the best goalkeeper in the world. He's not making errors you see time and time again. I'm very pleased with his work.
"I speak to David, but he's been at Man United nine years now and he's developed into a mature keeper, for me the best goalkeeper in the world. He's had fantastic seasons and I don't think it's a bad run to concede two goals in seven games against the teams we've played against. He's a mentally very strong keeper."
Solskjaer expects the formalities of Henderson's loan extension to be finalised shortly and is delighted his time with the Blades "has worked out as we wanted".
"It's a different job to be playing for Sheffield United and for Manchester United," Solskjaer said. "He's got different roles and for me, the two years he's had have been fantastic for his development. He's played with and against men, played in the Championship and plays now behind a team that play exciting football.
"And the stats show he's proved worthy of a few points with his saves. He's learning all the time, he's a passionate keeper, he's developing, he's had good coaching there and, for me, one day he'll be England number one and United number one and he needs to keep developing."
Solskjaer's men face Sheffield United at Old Trafford on Wednesday.